Various regulatory bodies, e.g., the Federal Aviation Administration (FAA) maintain standards for shielding RF emissions from aircraft and require aircraft to be tested periodically for compliance with the standards. Existing test methods require high RF transmission power to achieve sufficient dynamic range to measure shielding effectiveness. Such high RF transmission power require expensive amplifiers which can limit the availability of frequency spectrum required for the test. The limitations on frequency spectrum available can limit the accuracy of shielding effectiveness tests. Accordingly, systems and methods to test enclosed structures for RF shielding effectiveness may find utility.